1. Field of the Invention
The present invention relates to a manufacturing method of a substrate provided with a semiconductor layer with an insulating layer interposed therebetween, and particularly a manufacturing method of an SOI (silicon on insulator) substrate. Further, the present invention relates to a manufacturing method of a semiconductor device in which a substrate provided with a semiconductor layer with an insulating layer interposed therebetween is used.
2. Description of the Related Art
In recent years, integrated circuits using an SOI substrate where a thin single crystal semiconductor layer is formed on an insulating surface, instead of a bulk silicon wafer, have been developed. Since parasitic capacitance between a drain of a transistor and a substrate is reduced by using the SOI substrate, the SOI substrate has attracted attention as one improving performance of semiconductor integrated circuits.
One of the manufacturing methods of SOI substrates is a Smart Cut (registered trademark) method (e.g., see Patent Document 1). An outline of the manufacturing method of an SOI substrate by a Smart Cut method is described below. First, hydrogen ions are implanted into a silicon wafer by an ion implantation method to form a microbubble layer at a predetermined depth from the surface. Then, the silicon wafer into which the hydrogen ions are implanted is bonded to another silicon wafer with a silicon oxide film interposed therebetween. Then, by performing heat treatment, part of the silicon wafer into which hydrogen ions have been implanted is separated in a thin film shape along the microbubble layer which serves as a cleavage plane. Accordingly, a single crystal silicon film can be formed over the other bonded silicon wafer. Here, a Smart Cut method may also be referred to as a hydrogen ion implantation separation method.
Further, a method has also been proposed in which a single crystal silicon layer is formed over a base substrate made of glass by such a Smart Cut method (e.g., see Patent Document 2). Since glass substrates can have a larger area and are less expensive than silicon wafers and are transparent, the glass substrates are mainly used in manufacturing liquid crystal display devices and the like. By using such a glass substrate as a base substrate, a large-sized inexpensive SOI substrate can be manufactured.
In addition, a method of irradiating the single crystal silicon layer with a laser beam for improvement in crystal quality of the single crystal silicon layer is disclosed in Patent Document 2.
[Reference]
[Patent Document]
    [Patent Document 1] Japanese Published Patent Application No. H05-211128    [Patent Document 2] Japanese Published Patent Application No. 2005-252244